【導(dǎo)讀】1.觀察一列數(shù):1,-1,1,-1,1,-1,…,則第99個(gè)數(shù)是____,第100個(gè)數(shù)是____,第n個(gè)數(shù)是_______________.3.按規(guī)律排列的一列數(shù):3,5,7,9,11,…,那么第500個(gè)數(shù)是_______,4.一組按照規(guī)律排列的式子:x,_________行最后一個(gè)數(shù)是2020.9.有一個(gè)多項(xiàng)式為:-x+2x2-4x3+8x4-16x5+…,按此規(guī)律寫下去。,第100項(xiàng)是______________,第2017項(xiàng)是_________________,第n項(xiàng)。10.一組按規(guī)律排列的多項(xiàng)式:a+b,a2-b3,a3+b5,a4-b7,…12.已知整數(shù)a1,a2,a3,a4,…滿足下列條件:a1=0,a2=-|a1+1|,a3=-|a2+2|,a4=-|a3+3|,…,依此類推,則a2017的值為(). ×n-1n×n+1n=12×n+1n=n+12n